io.read seems not right on windws, why?

["R.wen" <rwen2012@...>]

hi,

   I just test the simple code as follow,

local f = io.open("lua53.dll")
print(f:seek("end"))
print(f:seek("set"))

local str = f:read("a")
print(#str)

it is output is:

230400
0
201

it only read out 201 bytes, but the file size is 230400, what is wrong here?

thanks,

rwen